What is the median of 20 21 22 23 24 25 26 27 28?

To find the median of a set of numbers, you first need to arrange them in numerical order. In this case, the numbers are already in order. Since there are 8 numbers in the set, the median will be the average of the two middle numbers. In this case, the two middle numbers are 23 and 24. Therefore, the median of this set is (23 + 24) / 2 = 23.5.